LOS ANGELES, March 25 (Reuters) -

A federal appealscourt on Monday upheld a federal judge's July ruling keepingsong-swap service Napster shut down until it can fully comply withan injunction to remove all copyright music.

Napster had no immediate comment.

The appeals court in July blocked U.S. District Judge MarilynPatel's ruling to keep Napster offline from being enforced pendingits ruling on the matter, although Napster never resumed operationsanyway.

The once high-flying pioneer of online music swapping went idlein July due to technical glitches in complying with the preliminaryinjunction issued by Patel in March of 2001, barring the trade ofany copyrighted material on its site.

The injunction came at the behest of major record labels, whichsued the company in 1999 accusing it of facilitating copyrightinfringement by allowing digital versions of their artists' songsto be shared for free, in many cases thousands of times each.

In an effort to join the mainstream, Napster in January begantesting a paid, secure online music service, but it has yet tosecure any licenses from the major labels who sued it for copyrightinfringement and it remains unclear how many of the some 60 millionusers it once attracted will return to the service.

"We affirm both the modified preliminary injunction and theshutdown order. The terms of the modified preliminary injunctionare not vague and properly reflect the relevant law on vicariousand copyright infringement," a three-judge panel of the Ninth U.S.District Court of Appeals in San Francisco said in its ruling.

"The shutdown order was a proper exercise of the districtcourt's power to enforce compliance with the modified preliminaryinjunction," the panel said.

Last month, Patel handed Napster a small victory, giving theservice time to gather evidence before ruling on a recordingindustry request for summary judgment in its copyright infringementlawsuit.